Device for indicating the useful pressure in engines.



IVLARNJJT. DEVIUE FOR INDICATING THE USEFUL PRESSURE IN ENGINES.

APPLICATION IILEI) MAB. 3, 1909.

Patented J an. 10, 1911.

525E Mk. L 3

r. 4 will:

MAX Armor, or

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A'IX-LILCHAPELLE, GERMANY.

To all whom it may concern:

Be it known that 1, MAX. ARNDT, a subject of the German Emperor, and residing at AiXda-Chapelle, Germany, have invented certain new and useful Improvements in Devices for Indicating the Useful Pressure in Engines, of which the following is a specification.

My invention relates to devices for recording the useful pressure of an engine, Which is to be indicated, insuch manner that the compression pressure is not meas ured and consequently only the effective useful pressure of the engine is recorded.

In the new device an electric current which depends on the movements of the indicator-prston passes through a measuring apparatus, so that the recorded current corresponds to the movements of the indicator. The movement or the indicator-piston which correspondsto the pressure in the engine during the compression, however, is

not measured. I

My invention substantially consists in providing a controlling device, connected with the indicator, for closing and ppening the circuit of the electric current hich is to be measured, the arrangement belhg such that the controlling device does notwork during the compression pressure, whereas during the admission pressure the indicator; piston reciprocates a contact on a number of contacts connected with resistances in the circuit In the accompanying drawing the device represented diagrammatically by way of example, Figure 1 showing one construe tional form, Whereas 2 shows a noditied form. 1

Referring to the drawing, S indicates the reversing device, J the indicator; denotes the cylinder of the differential. indicator which is connected by the pipes a, '1') with the two sides of the cylinder oi" the engine which is to be indicated. In front of and behind the piston 71; are arranged sprin f, F, the former in the chamber (1 and the latter in the chamber (1 of the indicator cylinder. The indicator piston-rod h is connectcd by means of a. link (E with a contact lever 2 c which is mounted in a bracket {j and carries at its free end a roller (1. The

ce parts 6 and e of the contact lever are [mechanically connected with one another in an insulsting sleeve '5 When the engine Specification of Letters Patent.

Application filed March 3, 1909.

Serial No. 481,059.

is being indicated the contact roller 0 rolls over two groups of electric contacts L L which are insulated from one another. The

contacts L are connected with a group of resistances XV and the contacts L with the group of resistances W The indicator piston-rod it has attached to it by means of an insulating member or sleeve 2' a tail rod h, on which is attached a boss t which, when the engine is being indicated, pushes a frame '1' alternately toward the one or the other side and thereby operates the two-way or reversing switch S. The controlling member t has so much play in the frame 9 that it. only hits the latter and moves it. to one side when the compression pressure is ended and the admission pressure begins on the opposite side of the indicator piston k, and accordingly the frame 1" is only switched over after one of the springs f or f has taken up the compression pressure. Vvith the electrically conducting frame r there are connected contact springs s '8 and s which are displacealolc between two insulating bars 6 and i the former of these bars carries two contacts Z Z and the latter a conductor Z. The contact Z connected by a conductor 1 with the group of resistances W The contact Z is connected through the conductor 2 with the group of resistances V The conductor Z is connected by 'way of a conductor 3, source of current i and a conductor with an electrical measuring instrument 2, the latter being connected by conductors (3 and 7 with the contactlever e". The flexible conductor '7 an move freely with the rocking lever a.

The device operates as follows: If pressure above atmospheric exists in, the cylindcr chamber a, the piston-rod ,lmoves to the left. and drives the roller 0 over a part of the resistance contacts I and silnultaneously the boss 6 drives the frame 9 to the left, whereby the contact a, Z is made and consequentlythe. following circuit closed :-batter y 4, lead 3, contact s,.. contact 8, contact Z, lead 1 roller a, lever 6 leads 7 and (3, measuring instrument and lead The current, which has to pass through a definite number of sections of the resistance lV corresponding to the position oi the rollene, is measured in the instrument The further the roller 0 is deflected to the left, the tower resistauccs are in the circuit. The ContlllctOI 2 is without current Patented Jan. 10, 1911.

v' pin 14, crank 9 during this movement of the piston-rod [L to the left. If the chamber 0 of the indicator giylinder has a pressure above atmospheric, ie piston-rod h. moves to the right, clrses 5 the contact 8 Z and closes the following circuit-source of current l, lead 3, contact 8 contact 8 contact Z lead 2, roller 6, lever '6 leads '7 and 6, instrument 2, and lead 5. When the piston-rod h is moved, the roller 6 is simultaneously moved over the contacts L and a number of sections of the resistance is cut out. When the reversal of stroke of the engine occurs the electric circuit is alternately interrupted in the one group of contacts L but is closed in the other group of contacts L on the contrary, and reversely, and as each reversal of stroke of the engine coincides with the end of a compression pressure and with the commencement of an admission pressure, only i that group of contacts: receives current on which the contact roller 6 is'placed by the useful pressure, whereas the compression pressure moves the contact roller 6 always onto a contact L or L without current.

In the modified form of the device represented in Fig, 2 the reversing switch S is operated by a member 8 moved by the engine which is to be indicated; the engine is represented diagrammatically by cylinder C, piston K, piston-rod l0, crosshead .11, crosshead guide 12, connecting-rod 13, crank and crank-shaft 8. Both sides C and C of the steam-engine cylinder C are connected by pipes a and b with the differential indicator J, the pipe I) leading to the chamber 0 and the pipe (1 to the chamber 0 The indicator piston l1 and its pisroller 0 in like manner as in the form shown in Fig. 1, said roller being movedon the groups of contacts L and L when the engine is being indicated.

- The reversing switch S consists of a semicircular conductor t provided with insulation 2' and connected by means of the disk 6 fixed on the crank-shaft 8 with the engine which is to be indicated in such manner that during the compression periods the contacts s .9 and .9, s are not closed. The con tact s is connected by a conductor 1 with the group of resistances and the contact 8 by the conductor 2 with the group of resistances W contrary, are connected by conductors 3, 3

and 3, source of current 4: and conductor 5 with the counter or measuring instrument 2-, and the latter is connected by conductors G and 7 with the contact lever e of the indica tor J. I

Iclaim: I a

1. In means for continuously, measuring the useful pressure in an engine cylinder, the combination, with an engine indicator having a piston, of a source of current, a

ton-rod it are connected with a,- contact' The contacts a" and at, on the and means measuring instrul'nent connected with one pole of the latter, two groupsfof resistances each provided with a series of contacts, means electrically connected with said instrument and mechanically connected with the piston of the indicator movable on said contacts, and switching means electrically connected with said resistances and with the other pole of the source of current, hand operated in dependence on the useful ressure at the two sides of the piston o the engine which is being indicated, for closing electrically with said groups of resistances and with the other pole of the source of current and connected mechanically with lay with the piston of the indicator, as set ibrth. I

3. In means for continuously measuring the useful pressure in-an engine cylinder, the combinatiomwith an engine indicator having apiston, of a source of current, a measuring instrument connected with one pole of the latter, two groups of resistances each provided with a series of contacts, a contact lever electrically connected with said instrument and mechanically connected with the piston of the indicator movable on said contacts, and a reversing switch comprising two snitch-contacts each connected with one of said groups of resistances, a sWitcl1-contact connected with the other pole of the source of current, a tail rod h aving a boss driven. by the indicator piston, an electrically conducting rame inclosin r said boss and movable freely on said tail r0 a spring on said frame continually contacting the latter switch-contact, and another spring on. said frame adapted to always contact one or the other of the former switch-contacts.

4:. In a device of the class described, the combination with an engine indicator cylinder and piston; of a source of current, an electrical measuring instrument connected with one pole of the latter, two groups of resistances, each group of which is provided with contacts, means electrically connected with said instrument and mechanically connected with said piston and movable over said contacts, an electrical switch to send current alternately through said groups of resistances, to automatically actuate the switch.

5. In a device of the class described, the

combination in an electrical circuit havin therein a source of current, an 61601311025 measuring instrument and two groups of resistances and their. contacts; of steam actuated means included in said circuit to operate in connection with said contacts and resistances, and steam actuated means to alternately send current to the groups of resistances after the compression in the engine to be indicated has ceased. 10 In testimony whereof, I'affix my signature in the presence of two Witnesses.

MAX ARNDT. Witnesses HENRY QUADFLIEG, ELISE KOELBUsCH. 

